1. Field of the Invention
The present invention relates to a digital television and more particularly, to an image zooming apparatus of a digital television.
2. Discussion of Related Art
A digital television (DTV) has many functions including functions which had only been available through a computer. Among these functions, a function for zooming to view a portion of a display is also available in analog televisions. In the zoom function of an analog television, an output image is enlarged by controlling the horizontal and vertical of the electron beam emitted from an electron gun of a CRT.
As shown in FIG. 1, a zooming function may be implemented by converting an input signal into a digital signal and by adding a zoom controller and memory. Particularly, a channel tuned in by a tuner 101 is demodulated into a video signal and an audio signal through an audio/video (A/V) processor 102. The demodulated signals are then digitalized in an analog/digital (A/D) converter 103. The digitalized signal is stored in a memory 106 of a zoom processor 104, from which only a signal of a corresponding area is output to an interpolator according to the control of a zoom controller 105. Thereafter, the interpolator 107 interpolates the received signal to a size based upon a zoom magnification, and the magnified signal is stored in a second memory 109. The data stored in the memory 109 is finally output to a display device according to the control of a display controller 108.
Although the analog system as described above allows a function of zooming, the zooming is only available for a particular areas. Also, the magnification is significantly limited. As a result, a user or viewer is restricted in zooming a desired area by various magnifications. An interested area cannot be re-zoomed a multiple times because there is no multi-step zooming function, thereby causing an inconvenience to the user.
Accordingly, an object of the present invention is to solve at least the problems and disadvantages of the related art.
An object of the present invention is to provide an image zooming apparatus for a digital TV capable of zooming an optional area of an image in a vertical direction.
Another object of the present invention is to provide an image zooming apparatus for a digital TV capable of zooming and displaying an image by various magnifications.
A further object of the present invention is to provide an image zooming apparatus for a digital TV capable of re-zooming a specific area of an image by user manipulation.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objects and advantages of the invention may be realized and attained as particularly pointed out in the appended claims.
To achieve the objects and in accordance with the purposes of the invention, as embodied and broadly described herein, the image zooming apparatus of a digital TV includes a line memory unit for storing the input images by each line; an input data controller for storing the input data in the line memory unit according to a type of the input image and a zoom magnification; a zoom controller for receiving zoom area information and zoom magnification from a user, and controlling the data storage in the line memory unit and the processing of the stored data; and a data processor for outputting a zoomed image from an original image stored in the line memory unit according to the control of the zoom controller.
In the present invention, a method of interpolating a zoom image depends upon the number of line memories. Also, in the input data controller, the luminance (Y) data operates to determine a storing procedure of the line memory according to the magnitude of an input image and the zoom magnification, regardless of the input image type. Moreover, the color (C) data among the input images operates to determine a storing procedure of the line memory according to the magnitude of an input image, the zoom magnification, and a type of the input images and color formats of output images.
Furthermore, in the present invention, a user selects a zooming position and magnification from an output image. The zoom controller then determines a zoom starting position on an original image and a desired input size based upon the selected position and magnification. Finally, the zoom controller performs a control operation such that 1/(n2) size of the original image may be zoomed to a size of the output image, where the width and length are respectively zoomed by an n magnification and where n is a natural number.